Robert S. Feranec, Andrew L. Kozlowski, 2018. "Onset age of deglaciation following the Last Glacial Maximum in New York State based on radiocarbon ages of mammalian megafauna", Quaternary Glaciation of the Great Lakes Region: Process, Landforms, Sediments, and Chronology, Alan E. Kehew, B. Brandon Curry

ABSTRACT

Developing accurate chronologies is important for understanding the formation and evolution of glacial environments in the Quaternary. Radiocarbon dating is a prominent technique for creating chronologies for glacial events during the late Pleistocene, and although radiocarbon dates from vertebrate fossils are relatively abundant, these dates have been underutilized for timing glacial events. Here, the utility of using radiocarbon dates from large mammal fossils for dating glacial events is explored further. Specifically, this study examines the potential of exclusive use of dated mammal remains to establish a chronology of deglaciation in New York State after the Last Glacial Maximum. We predict the earliest occurrence dates of megafauna to represent a minimum age for the initiation of deglaciation because glacial ice would have needed to have melted for plants and animals to begin to inhabit the state. We also predict dates to progress to more recent ages from south to north following recession of the Laurentide ice sheet. The data support these predictions. The earliest occurrence dates for mammoth and caribou, the suspected first large mammal species to occur within the state, are between 17,470 and 16,430 calibrated yr B.P. These dates imply first occurrence of large mammals in New York State and thus a minimum age of deglaciation beginning ca. 17,000 calibrated yr B.P. Because of the likely delay between the timing of deglaciation and the first mammal inhabitants of the state, this date must be viewed as a minimum age, with deglaciation having occurred sometime prior to this age. Comparing south to north, as an indicator of glacial regression, dates from New York State south of 42°N latitude are earlier compared to dates collected north of this latitude. This progression of dates from south to north supports the prediction that megafauna expanded northward following recession of the Laurentide ice sheet, and it implies that radiocarbon-dated mammalian megafauna data are useful, even exclusively, in identifying the timing of certain glacial events.

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